Iron superconductor has a critical temperature above liquid nitrogen

A single layer film of an Iron superconductor has a critical temperature above liquid nitrogen. Liquid nitrogen cooled superconductors are far cheaper to operate than those that require lower temperatures.

Recent experiments on ​FeSe films grown on ​SrTiO3 (​STO) suggest that interface effects can be used as a means to reach superconducting critical temperatures (Tc) of up to 80 K. This is nearly ten times the Tc of bulk ​FeSe and higher than the record value of 56 K for known bulk Fe-based superconductors. Together with recent studies of superconductivity at oxide heterostructure interfaces these results rekindle the long-standing idea that electron pairing at interfaces between two different materials can be tailored to achieve high-temperature superconductivity. Subsequent angle-resolved photoemission spectroscopy measurements of the ​FeSe/​STO system revealed an electronic structure distinct from bulk ​FeSe, with an energy gap vanishing at around 65 K. However, ex situ electrical transport measurements have so far detected zero resistance—the key experimental signature of superconductivity—only below 30 K. Here, we report the observation of superconductivity with Tc above 100 K in the ​FeSe/​STO system by means of in situ four-point probe electrical transport measurements. This finding confirms ​FeSe/​STO as an ideal material for studying high-Tc superconductivity.

Influence of an external magnetic field on the zero resistance detected in 4PP transport measurement on another ​FeSe/​STO sample.

Nature Materials – Superconductivity above 100 K in single-layer ​FeSe films on doped ​SrTiO3

Growth and characterization of a high-quality single-layer film of ​FeSe.

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